Just posting a list of some supposedly live IDN-domains to inspire us all (found it at a registrar).
Chinese
http://阿诗玛.com/ Yunxi Hongta Tobacco Company: company site
http://红太阳电子商务.com/ Red Sun Group Corporation: company site
http://澳洲唐人街.com/ Australia Daily: news and information portal
http://浙江省运会.com/ Wenzhou Ruili GVM: sporting goods online store
http://名城苏州.com/ 2500sz.com: Suzhou information and portal
Danish
http://www.brændendekærlighed.com/ Brændende Kærlighed Theater Company: information site
http://www.øl.com/ Carlsberg Brewing Company: company site
Finnish
http://www.pääoma.com/ Pääoma: financial portal
http://www.mäkitorppa.com/ Mäkitorppa: company site
French
http://enténial.net/ Enténial Bank: company site
http://e-canapé.com/ Désio Furniture: company site
German
http://weingut-schönberger.com/ Weingut Schönberger Winery: company site
http://trüffelschwein.com/ Trüffelschwein: company site
Greek
http://www.δωδωνη.net/ Dodoni Ice Cream: company site
http://www.απασχοληση.com/ Apaxolisis: employment search site
Japanese
http://理容ナカムラ.com/ Nakamura Barber Shop: company site
http://きくどら.com/ Kikuna Driving School: company site
http://あーるいん.com/ Pension R.in: company site
http://e-革命.com/ Mitsui & Associates Telepark Corporation: company site
http://きかいほんやく.net/ Oki Electric Industry Company: company site
Korean
http://아이랑책이랑.com/ Eyerang-Chaekirang: online bookstore
http://바둑강좌.com/ Okdul Indus: game site
http://중고차.com/ Jungkocha: used car online store
http://자연생활의집.com/ Nature Living House: health information site
http://치아.com/ U&I Dental Clinic: company site
Spanish
http://viñexsa.com/ Viña Extremeña Winery: company site
http://peñafiel.net/ Peñafiel Tourism Bureau: information site
Swedish
http://räddabarnen.net/ Rädda Barnen (Save the Children, Sweden): organization site
http://internetdomänen.com/ Conactive Internet Services: company site